Zoop is interesting in that they tried to create a puzzle game that didn't borrow from Tetris. Balance issues, mostly because the blobs appear too fast, make this game incredibly difficult. Another issue is that the 4x4 grid you move around is difficult to manage with a d-pad. I think the game would have been much better if they had made it a 3x3 grid.

The Zoop prototype has an internal date of July 20, 1995. I couldn't find an exact release date for Zoop, but it appears to have been released sometime in October or November 1995. The game utilizes only one of the chip slots on the board (the game is only 4 Mb). I'm not sure on the origin, but surely something with this level of completion could have been used for magazine previews.

This prototype binary was the most different from the final binary of all the prototypes that Martin gave me (at 53%), so I thought I should do some hacking to find the cause of it. One thing I noted after hacking the game to make the game easier was that Viacom's claim that there are 99 levels is false. Once you get past level 99, the game continues, but the level counter does not increment. So in other words, the game has no true ending. Considering the difficulty, I doubt any gamer would be able to get to level 99 anyways.

The main difference in the prototype is that it takes different amounts of blobs to "zoop" in order to pass a level compared to the final (usually less). There is at least one music track (I think two) that are not in the final version. The tracks are random and it could just be that they are programmed to not happen very often, though. Likewise, there are a couple of tracks in the final version that are not in the prototype.

The main reason that the prototype appears so much different than the final binary stems from a displacement of the bytes. There is a section of the binary that starts at 0x42BA0 in the prototype and 0x42B00 in the final version, a difference of 0xA0. The section spans 136,384 bytes, or approximately 26% of the binary. Without the offset, this section is identical between the prototype and final versions. The other large section that looks different is where the background graphics are stored. When looking at it with a tile viewer, the binaries looks dramatically different, though in-game there is no noticeable difference. My guess is that they used a different compression or storage method.

The Zoop prototype is definitely a late beta or release candidate, and certainly isn't as different as I anticipated. It certainly makes a case for the need of careful examination of the binary before coming to any conclusions.